Every person, irrespective of whether he is healthy or not, has to at least once undergo an eye examination/treatment that requires pupil dilation. Those having various eye problems (e.g., macular degeneration, diabetes, etc.) require repeated pupil-dilated eye examinations. The pupil dilation (mydriasis) is typically induced by application of a dilator drug (typically atropine) to the patient's eye followed by waiting several minutes before the pupil is sufficiently dilated to enable the eye examination.
Various types of a dilator drug, known as mydriatic agents, have been developed. For example, WO 98/51292 discloses pharmaceutical compositions which include a therapeutically effective amount of a stereoscopically-pure enantiomer, preferably (+)-phenylephrine is substantially free of (−)-phenylephrine.
Furthermore, the conventional pupil dilation procedure results in a recovery period of a few hours, whilst the patient suffers from excessive light reaching the retina accompanied by focusing difficulties. Moreover in this recovery period, it is highly recommended that the patient will refrain from driving or doing dangerous tasks.
Constriction of a pupil size (miosis) is required for individuals suffering from excessive pupillary dilation, e.g., in dim light or through medication. Various drug-based treatments suitable to be used for this purpose are disclosed for example in the following patents: U.S. Pat. Nos. 6,730,065; 6,515,006; 6,420,407; 6,291,498.
It is known to use the principles of electrophoresis to assist the drug delivery process (e.g., deliver of vitamins, such as Vitamin C). Electrophoresis is an electrochemical process in which colloidal particles or molecules with a net electric charge migrate in a solution under the influence of an electric current. This process is also termed “iontophoresis” or “cataphoresis”.
U.S. Pat. No. 6,101,411 discloses a dilation enhancer apparatus, which is a hand held electrophoretic device using a contact lens type delivery system to provide rapid clinically useful dilation of the pupil of the eye. The apparatus includes a contact lens with a conductive outer shell (one electrode of a two-electrode electrophoresis device) and a preferably soft, preferably disposable contact lens for contacting a patient's eye that assists in delivering dilation drops or other medicaments to a patient's eye. Advantageously, the lens is used with a relatively small hand-held power source. Electrophoresis can be used to help deliver dilation drops more rapidly, regardless of the delivery apparatus used for the electrophoresis.